摘要
±500 kV伊穆直流极1线路发生瞬时性接地故障,由于双极线路之间的静电和电磁耦合作用,使极2直流电压发生波动,继而引起该极直流滤波器快速充放电,产生较大的穿越电流,而该组直流滤波的首端光电式电流互感器、尾端电磁式电流互感器在电流传变特性方面存在较大差异,穿越电流传变产生的差流达到保护动作条件,导致极2直流闭锁。针对这次保护误动,将直流滤波器差动保护延时由40 ms延长至500 ms,提高了保护的防误动水平。
Pole 2 DC voltage fluctuates due to electrostatic and electromagnetic coupling between bipolar circuit when ±500 kV Yi-MuHVDC pole 1 line instantaneity ground fault nccurrs, which can lead to Pole 2 DC filter rapidly charge and discharge, as well as pro-duce across current. Photoelectric CT＇s head and electromagnetic CT＇s tail are different greatly, difference stream can cause pole 2 bloc-king fault. According to this protection misoperation, differential protection of DC filter delays from 40 ms to 500 ms to improve thepreventive mal-operation leavel.
出处
《东北电力技术》
2015年第9期19-22,26,共5页
Northeast Electric Power Technology
